853 research outputs found
On the structures of moss colony in the Yukidori Valley, Langhovde, East Antarctica
The moss vegetation developing in the Yukidori Valley, Langhovde, East Antarctica, was investigated as based on the samples in the vertical cross-section housed as the herbarium specimens to categorize the structure of the moss colony and to determine the specific composition. The vegetation consists of pure colonies of one species, and mixed colonies composed of two or rarely three moss species. Each colony was classified by species composition and degree of unevenness. The active zone, decomposed zone which were seen in the vertical cross-section, and epiphytic condition on the surface such as cyanobacteria and imperfect lichens, and rhizoidal layers in the inside of colony were determined and measured. Furthermore, the relationship between epiphytic condition and the thickness of the pure and mixed colonies was discussed taking account of ecological significances of these structural features
Seasonal and regional differences in lighting conditions and their influence on melatonin secretion
The paper presents essential results of multidisciplinary research dealing with differences in lighting conditions (natural and/or artificial) and their possible influence on melatonin secretion studied in Fukuoka (Japan) and in Warszawa (Poland). Several characteristics of lighting were considered (intensity of global 0.4-3.0 μm, visible 0.4 0.76 μm solar radiation, illuminance (lux), peak irradiance (μW∙cm−2∙nm−1), Color Corresponded Temperature (CCT, K) and peak wave length (nm)). Diurnal cycle of melatonin secretion was examined at volunteers (Poland – 15, Japan – 18), young male and female (21–33 years). Saliva samples were collected at 3h intervals, beginning at 10:00h on Thursday with subsequent sampling times at 13:00, 16:00, 19:00, 22:00 and at 01:00, 04:00 07:00h on Friday. Melatonin concentration (MC) was measured by commercials ELISA kit tests
VLBI Monitoring Observations of Water Masers Around the Semi-Regular Variable Star R Crateris
We monitored water-vapor masers around the semi-regular variable star R
Crateris with the Japanese VLBI Network (J-Net) at the 22 GHz band during four
epochs with intervals of one month. The relative proper motions and
Doppler-velocity drifts of twelve maser features were measured. Most of them
existed for longer than 80 days. The 3-D kinematics of the features indicates a
bipolar expanding flow. The major axis of the asymmetric flow was estimated to
be at P.A. = 136 degrees. The existence of a bipolar outflow suggests that a
Mira variable star had already formed a bipolar outflow. The water masers are
in a region of apparent minimum radii of 1.3 x 10^12 m and maximum radii of 2.6
x 10^12 m, between which the expansion velocity ranges from 4.3 to 7.4 km/s.
These values suggest that the water masers are radially accelerated, but still
gravitationally bound, in the water-maser region. The most positive and
negative velocity-drifting features were found relatively close to the systemic
velocity of the star. We found that the blue-shifted features are apparently
accelerated and the red-shifted apparently decelerated. The acceleration of
only the blue-shifted features seems to be consistent with that of the
expanding flow from the star.Comment: 15 pages, 5 figures, Accepted for publication in PASJ (2001),
preprint can be obtained via WWW on
http://www.nro.nao.ac.jp/library/report/list.htm
Lingula rostrum collected from the Seto Inland Sea (Brachiopoda, Inarticulata, Lingulidae)
日本の代表的な内海である瀬戸内海より得られたドングリシャミセンガイLingula rostrum(Shaw, 1798)の外部形態,および,分子生物学的な比較検討を行った。試料は瀬戸内海の岡山県沖備讃瀬戸より得られたドングリシャミセンガイを用い,倉持ら(2012)によるミドリシャミセンガイLingula anatina(奄美大島産)とウスバシャミセンガイLingula reevii(有明海産)の報告と比較した。ドングリシャミセンガイ(備讃瀬戸産)は,殻の形態,および,生時の肉茎の色彩により,外部形態でミドリシャミセンガイ,ウスバシャミセンガイと区分される。
また,ドングリシャミセンガイ(備讃瀬戸産)の18S rRNA 遺伝子の塩基配列を,ミドリシャミセンガイ(奄美大島産)とウスバシャミセンガイ(有明海産)と比較したところ,ドングリシャミセンガイ(備讃瀬戸産)は,ミドリシャミセンガイ,および,ウスバシャミセンガイの両種とは異なるクレードに属することがわかり,分子系統的にも離れた分類群として扱われるべきであることが示唆された。The brachiopod Lingula rostrum (Shaw, 1798) collected from Japanese waters was compared morphologically and phylogenetically in terms of shell morphology with L. anatina and L. reevii (Kuramochi et al, 2012). 18S rRNA gene sequences were also compared with other Lingula species. The specimens of L. rostrum, L. anatina, and L. reevii were collected from Seto Inland Sea (Off-Okayama, Bisanseto), Amami-Ohshima Island, and Ariake Sea, respectively, and used for comparison. The shell of L. rostrum was distinguished from L. anatina and L. reevii by allometric morphology and fresh tissue coloration. Based on the 18S rRNA gene sequences of L. rostrum along with those from L. anatina, L. reevii, and other species registered in a DNA database, a phylogenetic tree was constructed. The brachiopod L. rostrum was placed in a separate clade from other Lingula species, which suggests that L. rostrum should be regarded as non-closely related species
Layer-specific expression of extracellular matrix molecules in the mouse somatosensory and piriform cortices
In the developing central nervous system (CNS), extracellular matrix (ECM) molecules have regulating roles such as in brain development, neural-circuit maturation, and synaptic-function control. However, excluding the perineuronal net (PNN) area, the distribution, constituent elements, and expression level of granular ECM molecules (diffuse ECM) present in the mature CNS remain unclear. Diffuse ECM molecules in the CNS share the components of PNNs and are likely functional. As cortical functions are greatly region-dependent, we hypothesized that ECM molecules would differ in distribution, expression level, and components in a region- and layer-dependent manner. We examined the layer-specific expression of several chondroitin sulfate proteoglycans (aggrecan, neurocan, and brevican), tenascin-R, Wisteria floribunda agglutinin (WFA)-positive molecules, hyaluronic acid, and link protein in the somatosensory and piriform cortices of mature mice. Furthermore, we investigated expression changes in WFA-positive molecules due to aging. In the somatosensory cortex, PNN density was particularly high at layer 4 (L4), but not all diffuse ECM molecules were highly expressed at L4 compared to the other layers. There was almost no change in tenascin-R and hyaluronic acid in any somatosensory-cortex layer. Neurocan showed high expression in L1 of the somatosensory cortex. In the piriform cortex, many ECM molecules showed higher expression in L1 than in the other layers. However, hyaluronic acid showed high expression in deep layers. Here, we clarified that ECM molecules differ in constituent elements and expression in a region- and layer-dependent manner. Region-specific expression of ECM molecules is possibly related to functions such as region-specific plasticity and vulnerability
Helping-Like Behaviour in Mice Towards Conspecifics Constrained Inside Tubes
Prosocial behaviour, including helping behaviour, benefits others. Recently, helping-like behaviour has been observed in rats, but whether it is oriented towards rescue, social contact with others, or other goals remains unclear. Therefore, we investigated whether helping-like behaviour could be observed in mice similar to that in rats. Because mice are social animals widely used in neuroscience, the discovery of helping-like behaviour in mice would be valuable in clarifying the psychological and biological mechanisms underlying pro-sociability. We constrained mice inside tubes. Subject mice were allowed to move freely in cages with tubes containing constrained conspecifics. The subject mice released both cagemates and stranger mice but did not engage in opening empty tubes. Furthermore, the same behaviour was observed under aversive conditions and with anesthetised conspecifics. Interestingly, hungry mice opened the tubes containing food before engaging in tube-opening behaviour to free constrained conspecifics. Mice showed equal preferences for constrained and freely moving conspecifics. We demonstrated for the first time that mice show tube-opening behaviour. Furthermore, we partly clarified the purpose and motivation of this behaviour. An effective mouse model for helping-like behaviour would facilitate research on the mechanisms underlying prosocial behaviour
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